release/0.8/beta2

Integrate Adjust

Fix toast messaege truncated issue on low-res devices

Update proguard rules to dontobfuscate

Update release app icon(normal/adaptive)

Merge pull request mozilla-tw#246 from benjamin-cheng/benjamin/l10/18…

…0925-import-e16b2f0

Import from l10n repo e16b2f0